BIO 206SPRING SEMESTER 2019INSTRUCTOR: DR. RITA MOYES25 February 2019Parasitic Fungi● The enzyme lysozyme apparently plays a role in invasion○ The fungus then digests cell components and absorb nutrients● As cells die, the fungus invades adjacent cells and continues to digest and absorb● Example:○ Oak wilt at TAMU■ Breaks down H2O conduits■ Fungi spread through the root system● Matts on trees● Exudes a fruity odor that attracts insects especially beetles● The insects pick up and spread spores■ Treatment is very difficult● Fungicide● Deep trenches● Remove infected treesFungal Diseases (Mycoses)● Systemic mycoses: deep within the body○ Throughout bloods and organs● Subcutaneous mycoses: beneath the skin○ Living tissues● Cutaneous/superficial mycoses: affect hair, skin, and nails, localized, e.g., hairshafts1● Opportunistic mycoses: takes advantage of a cut to enter the body○ Caused by normal microbiota or environmental fungiFungal Human Diseases● Cutaneous mycoses/dermatomycoses-ringworms or tineas○ Occur worldwide and represent the most common fungal diseases inhumans■ Tinea corporis → ringworm■ Tinea pedis → athlete’s foot■ Tinea cruris → jock itch (groin)● All caused by various Trichophyton species● Candida albicans- nosocomial pathogen○ Yeast infections○ HAI-healthcare acquired infections○ Part of the normal flora- GI tract, nouth, and vagina■ Opportunistic○ Does not usually cause disease → bacteria normal flora suppresses growth→ keeps them in check■ Immune system helps to keep yeast in check■ Change occurs: a decrease (i.e. taking antibiotics/other drugs)○ Absence of normal flora=yeast proliferates and causes disease○ Oral candidiasis (thrush) = infect neonate during birth■ Thrush in immunocompromised individuals→ systemic candidiasis● AIDs/ diabetes● Corticosteroid usages● Denture wearers○ Candidal vaginitis→ transmitted during sexual intercourse (STI)■ Discharge is curd-like■ Vaginal canal-lactobacillus sp (produces lactic acid which lowers thepH)■ Change occurs→ alkaline= overgrowth of yeast (transmitted duringthe birth process)○ Treatment with intravaginal drugs2■ Effective/safe for baby■ Pregnancy- hormone changes → change in pH of vagina● ~90% of women have a yeast infection during the thirdtrimester3. Fungi- produce mycotoxins● Aspergillus flavus produces aflatoxins○ That are highly toxic and carcinogenic to animals and humans○ These toxins are the most potent carcinogens (cancer causing agents) yetdiscovered■ Liver cancer○ Infests corn and peanuts■ Must screen for aflatoxin before being used for the food industry● Checked using fluorescence● Example 2○ Claviceps purpurea parasitizers rye and wheat causing the formation of thetoxin ergot○ Ergotism- the toxic condition in humans and animals■ Gangrene, psychotic delusions, nervous spasms, abortion, andconvulsions○ Most grains grown in the US are genetically resistant to the ergot fungus butmany strains grown in other parts of the world are